Temperature control circuit



1944- F. G. BOUCHER 2,356,206

TEMPERATURE CONTROL CIRCUIT Filed Feb. 25, 1941 /za/m 6M INVENTOR.

BY PJu ATTORNEY UNITED STATES PATENT OFFICE TEMPERATURE CONTROL CIRCUIT Frank G. Boucher, Houston, Tex., asslgnor to StandardOil Development Company, a corporation of Delaware Application February 25, 1941, Serial No. 380,510

1 Claim.

The present invention is directed to a highly sensitive relay system of the type used in temperature control circuits, and the like.

In extremely sensitive temperature control circuits associated with heating means it is neceshaving a moving arm 5, the movement of which is controlled by a coil 6 arranged in the field of a magnet I. The current to coil 6 is supplied by a battery 8 and the circuit has a pair of contacts 9 arranged in a capillary column l of mersary in order to obtain the desired sensitivity cu y w c i arranged in t chamber n which to use a mercury column of capillary proportions. the temperature is to be controlled- Since there is a limit to the current which can As will be seen when the mercury rises in colbe passed through this column between contacts 1 1 I0 fl e y to connect t contacts arranged in it, it is necessary to use in conjunco the moving coil relay 6 opens the circuit of battion with it a delicate relay which responds to tery 4 which in t causes relay 3 t p after small changes of current. This delicate relay, h passage f its e lag p r opening the however, becomes troublesome when the system heating circuit of battery 2. Then when the is arranged in a device which must be transtemper t r p b k n the c nt ct b we n ported, and is, therefore, subject to jarring, beit points 9, the reverse ope a o ta es P a cause mechanical Jars will operate the relay and tal operation f the mov n oil r lay interfere with the temperature control. due j n of the sy te o ot a ct t e The principal object of the present inv t heating current because such operation will break isto provide in a system of the character dethe battery circuit 4 Only om y which scribed a means for preventing the fluctuations not Provide sumcient time to Operate relay 3 in the current supplied to the heating means which will remain closed. due to this chattering or erratic behavior of the The nature and Objects of the Present invensensitive relay. Normally, this is done, according tion avi e thus described and illustrated. t0 the p t ent on, by inter-posing bet what is claimed as new and useful and is desired the sensitive relay and the cur t to be com 5 to be secured by Letters Patent is: trolled a current delay relay which has such a In a device which in use is subjected to Vlbme time lag that l d t respond to t chattertion and has a temperature control circuit utilizing of the se m relay ing a capillary column of mercury, in combina- The present, inve ti may be better under tion, a pair of contacts arranged in said column, stood from th f ll wl detailed descrlpuon f an electrical circuit containing said contacts and the accompanyin d a m which the single also including a highly sensitive relay capable figure is a schematic view of a system according of Operating a Very small current and being to the present invention, of a nature such as to be subject to undesirable Referring t t drawlng in detail. numeral operation due to vibration, a second circuit condesignates a heating coil supplied with current trolled by'sald relay and cmtammg a time delay by a battery 2, It wil b understood that m relay having a circuit opening lag suitable for practice this heating coil will be arranged in a the temperature control function of the (311mm; casing or chamber in the manner in which heatand sumciehtly 10h! to be unaffected y n lng coils are customarily disposed the circuit sirable operation of said sensitive relay due to of the heating coil is a time delay relay 3 which 40 vibration, and a third circuit supplying the heatis supplied with current by a battery 4. In the circuit of the time delay relay is an extremely sensitive relay which is of the moving coil type ing current controlled by said time delay relay.

FRANK G. BOUCHER. 

